C55

The McIntosh C55 is a stereo preamplifier with 16 inputs, network connectivity and flexible analogue and digital outputs. It follows the C53 and is designed to act as the control centre for a home audio system.

The C55 has 9 analogue inputs and 7 digital inputs. Its analogue connections comprise 3 balanced inputs, 4 unbalanced inputs and 2 phono inputs, each configurable for Moving Coil or Moving Magnet cartridges. Both phono inputs provide adjustable gain in 6dB steps from 40dB to 64dB, together with RIAA equalisation.

Digital conversion is handled by the DA2 Digital Audio Module, which uses a Quad Balanced, 8-channel, 32-bit Digital-to-Analogue Converter. The module includes an audio-only HDMI Audio Return Channel (ARC)1 input for routing television sound through a stereo system. Dolby® and DTS® multi-channel formats are converted to 2-channel audio.

The remaining 6 digital inputs are 2 coaxial, 2 optical, 1 USB and 1 MCT. The USB input supports DSD512 and DXD 384kHz, while the coaxial and optical inputs decode digital music up to 24-bit/192kHz. The MCT input provides a secure, custom DSD connection for use with McIntosh MCT series SACD/CD Transports. The DA2 module can be replaced by a future module if new digital technologies become available.

Three stereo pairs of variable balanced and unbalanced outputs provide connections to power amplifiers. All 3 output pairs can operate at the same time, allowing the C55 to send a source signal to 3 separate audio systems.

The Main output and Output 1 include adjustable High Pass and Low Pass filters for bi-amping a single speaker system. The High Pass outputs can be connected to a vacuum tube amplifier and the Low Pass outputs to a solid-state amplifier. Adjustable crossover settings allow the amplifiers to be matched to the speaker specifications and listening preferences. Output 1 also has trim level control for balancing the volume of 2 amplifiers in a bi-amped system.

Output 2 can be configured for mono or stereo operation. It can feed a stereo system in another room, 1 mono subwoofer or 2 separate stereo subwoofers.

The McIntosh C55 also includes a Processor Loop, which was not available on the last few generations of McIntosh preamplifiers. This connection allows an external signal processor, such as the MQ112 Environmental Equalizer or MEN220 Room Correction System, a dynamic range expander or another device to be inserted without placing it between the preamplifier and power amplifier. It can also be used with an analogue tape recorder, high-end cassette deck or 3-head reel deck, allowing a recording to be monitored shortly after it is made.

Control is available from the supplied remote control and front panel controls. The C55 can also be connected to a network for control through the complimentary Connect app, scheduled to be available April 2024, for Android and Apple devices. The app provides control of key functions including volume, input selection and output selection.

Select McIntosh source components3 connected to the C55 with a data cable can be partially controlled through the app's Source Control feature. This includes changing radio stations on a tuner and playing a disc in a CD player. The feature is intended for systems with a secondary set of power amplifiers and speakers connected to one of the C55 outputs, including an outdoor system that can be controlled without returning indoors.